\documentclass{article}

\begin{document}

\section{Demo of Sweave}

The following code snippets demonstrate how Sweave can be used to
implement literate programming.

<<>>=
fm <- lm(Ozone ~ Wind + Temp, data = airquality, na.action = na.exclude)
summary(fm)
@ 

Here are some residual plots.

<<fig=TRUE,echo=FALSE,height=4>>=
plot(residuals(fm) ~ fitted(fm))
@ 

<<fig=TRUE,echo=FALSE,height=4>>=
plot(residuals(fm) ~ airquality$Temp)
@ 

<<fig=TRUE,echo=FALSE,height=4>>=
plot(residuals(fm) ~ airquality$Wind)
@ 

\end{document}